Synergistic insecticidal compositions

ABSTRACT

The present invention provides a synergistic insecticidal composition comprising as essential active ingredients a neuronal sodium channel antagonist and an arylpyrrole insecticide. 
     Also provided are methods for synergistic insect control and crop protection.

This application is a division of Ser. No. 09/521,988 filed Mar. 9, 2000 now U.S. Pat. No. 6,342,518, which claims benefit of No. 60/124,228 filed Mar. 12, 1999, and claims benefit of No. 60/158,202 filed Oct. 7, 1999

BACKGROUND OF THE INVENTION

Although insecticidal agents and compositions have been developed to control insect pests such as agrohorticultural pests or hygienic pests, and in practice have been used as a single or a mixed agent, economically efficient and ecologically safe insect control compositions are still being sought. Insecticidal compositions which allow for reduced effective dosage rates, increased environmental safety and lower the incidence of insect resistance are highly desirable. The rotational application of insect control agents having different modes of action may be adopted for good pest management practice, however, this approach does not necessarily give satisfactory insect control. Combinations of insect control agents have been studied, however, a high synergistic action has not always been found. Obtaining an insecticidal composition which demonstrates no cross-resistance to existing insecticidal agents, no toxicity problems and little negative impact on the environment is extremely difficult.

Therefore, it is an object of this invention to provide a synergistic insecticidal composition which demonstrates a high controlling effect with concomittant reduced crop production cost and reduced environmental load.

It is another object of this invention to provide methods for synergistic insect control and enhanced crop protection.

SUMMARY OF THE INVENTION

The present invention provides a synergistic insecticidal composition comprising as essential active ingredients a synergistically effective amount of a neuronal sodium channel antagonist and an arylpyrrole insecticide.

The present invention also provides a method for synergistic insect control which comprises contacting said insect with a synergistically effective amount of a combination of a neuronal sodium channel antagonist and an arylpyrrole insecticide.

The present invention further provides a method for the enhanced protection of plants from infestation and attack by insects.

DETAILED DESCRIPTION OF THE INVENTION

When two or more substances in combination demonstrate unexpectedly high biological activity, for example, insecticidal activity, the resulting phenomenon may be referred to as synergism. The mechanism of synergism is not fully understood, and quite possibly may differ with different combinations. However, the term synergism, as used in this application designates a cooperative action encountered in a combination of two or more biologically active components in which the combined activity of the two or more components exceeds the sum of the activity of each component alone.

Surprisingly, it has now been found that a composition which comprises a combination of a neuronal sodium channel antagonist and an arylpyrrole insecticide provides superior insect control at lower levels of the combined active agents than may be achieved when the neuronal sodium channel antagonist or the arylpyrrole insecticide is applied alone.

As used in this application, the term neuronal sodium channel antagonist designates a compound which is capable of preventing the ability of a neuron cell to transfer sodium ions across the cell membrane. A neuron cell thus affected is unable to fire, resulting in paralysis, and ultimately mortality, in the target host. Descriptions of neuronal sodium channel antagonists and their mode of action may be found in Pesticide Biochemistry and Physiology, 60: 177-185 or Archives of Insect Biochemistry and Physiology, 37: 91-103, both of which are hereby incorporated by reference.

Neuronal sodium channel antagonists include compounds such as those described in U.S. Pat. Nos. 5,543,573; 5,708,170; 5,324,837 and 5,462,938, among other publications. Exemplary of the neuronal sodium channel antagonist compounds useful in the composition of this invention are those compounds having the structural formula

wherein

A is CR₄R₅ or NR₆;

W is O or S;

X, Y, Z, X′, Y′ and Z′ are each independently H; halogen; OH; CN; NO₂; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₃alkoxy, C₁-C₃haloalkoxy, C₃-C₆cycloalkyl, C₂-C₆alkenyloxy or sulfonyloxy groups;

C₁-C₆alkoxy optionally substituted with one or more halogen, C₁-C₃alkoxy or C₃-C₆cycloalkyl groups;

C₁-C₆alkoxycarbonyl, C₃-C₆cycloalkylcarbonyloxy, phenyl optionally substituted with one or more halogen, C₁-C₄alkyl, or C₁-C₄alkoxy groups;

aminocarbonyloxy optionally substituted with one or more C₁-C₃alkyl groups;

C₁-C₆alkoxycarbonyloxy; C₁-C₆alkylsulfonyloxy;

C₂-C₆alkenyl; or NR₁₂R₁₃;

m, p and q are each independently an integer of 1, 2, 3, 4, or 5;

n is an integer of 0, 1 or 2;

r is an integer of 1 or 2;

t is an integer of 1, 2, 3 or 4;

R, R₁, R₂, R₃, R₄ and R₅ are each independently H or C₁-C₄alkyl;

R₆ is H, C₁-C₆alkyl, C₁-C₆haloalkyl, C₁-C₆alkoxyalkyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkylcarbonyl, C₁-C₆alkoxycarbonyl, C₁-C₆alkylthio, or C₁-C₆haloalkylthio;

R₇ and R₈ are each independently H; halogen; C₁-C₆alkyl; C₁-C₆alkylcarbonyloxy; or phenyl optionally substituted with one or more halogen, CN, NO₂, C₁-C₆alkyl, C₂-C₆haloalkyl, C₁-C₆alkoxy or C₁-C₆haloalkoxy groups;

R₉ and R₁₀ are each independently H, or C₁-C₄alkyl;

R₁₁ is H, C₁-C₆alkyl, C₁-C₆haloalkyl, C₁-C₄alkylcarbonyl, C₁-C₆alkoxycarbonyl, or C₁-C₆haloalkoxycarbonyl;

R₁₂ and R₁₃ are each independently H or C₁-C₆alkyl;

G is H; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₄alkoxy, C₁-C₆haloalkoxy, CN, NO₂S(O)_(u)R₁₄, COR₁₅, CO₂R₁₆, phenyl or C₃-C₆cycloalkyl groups;

C₁-C₆alkoxy; C₁-C₆haloalkoxy; CN; NO₂; S(O)_(u)R₁₇; COR₁₈; CO₂R₁₉; phenyl optionally substituted with one or more halogen, CN, C₁-C₃haloalkyl, or C₁-C₃haloalkoxy groups;

C₃-C₆cycloalkyl; or phenylthio;

Q is phenyl optionally substituted with one or more halogen, CN, SCN, NO₂, S(O)_(u)R₂₀, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxyalkyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, or NR₂₁R₂₂ groups;

u is an integer of 0, 1 or 2;

R₁₄, R₁₅, R₁₆, R₁₈, R₁₉, R₂₁ and R₂₂ are each independently H or C₁-C₆alkyl;

R₁₇ and R₂₀ are each independently C₁-C₆alkyl or C₁-C₆haloalkyl;

R₃₃ is CO₂R₃₄;

R₃₄ is H, C₁-C₆alkyl, C₁-C₆haloalkyl, phenyl or halophenyl; and the dotted line configuration

represents a double bond or a single bond (i.e. C—N or C═N); or

a stereoisomer thereof.

Preferred neuronal sodium channel antagonists suitable for use in the composition of the invention are those compounds of formula I, II or III wherein the dotted line configuration represents a double bond.

More preferred neuronal sodium channel antagonists suitable for use in the inventive composition are those compounds of formula I or formula III wherein the dotted line configuration represents a double bond.

Particularly preferred neuronal sodium channel antagonists useful in the composition of the invention are those compounds of formula I or formula III wherein W is O; X is trifluoromethoxy and is in the 4-position; Y is trifluoromethyl and is in the 3-position; Z is CN and is in the 4-position; A is CH₂; n is 0; m, p and q are each 1; R and R₁ are each H; Z′ is Cl; R₃₃ and G are each CO₂CH₃; Q is p-(trifluoromethoxy)phenyl; and the dotted line configuration represents a double bond; or a stereoisomer thereof.

Further neuronal sodium channel antagonist compounds include those described in U.S. Pat. Nos. 5,116,850 and 5,304,573, among other publications. Exemplary of further neuronal sodium channel antagonist compounds suitable for use in the composition of the invention are those compounds having structural formula

wherein

W is O or S;

X″ and Y″ are each independently H; halogen; CN; SCN; C₁-C₆alkyl optionally substituted with one or more halogen, NO₂, CN, C₁-C₄alkoxy, C₁-C₄alkylthio, phenyl, halophenyl, C₁-C₄alkylsulfonyl, C₁-C₄haloalkylsulfonyl, or C₁-C₄alkoxycarbonyl groups;

C₂-C₄alkenyl; C₂-C₄haloalkenyl; C₂-C₄alkynyl; C₂-C₄haloalkynyl; C₃-C₆cycloalkyl; C₃-C₆halocycloalkyl; phenyl optionally substituted with one or more halogen, CN, NO₂, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₄alkylthio, C₁-C₄alkylsulfonyl or C₁-C₄haloalkylsulfonyl groups;

C₁-C₄alkylcarbonyl; C₁-C₄haloalkylcarbonyl; or

NR₂₈R₂₉;

m is an integer of 1, 2, 3, 4, or 5;

G′ is phenyl optionally substituted with one or more groups which may be the same or different selected from X″;

a 5-membered heteroaromatic ring containing one or two heteroatoms selected from 0 or 1 oxygen, 0 or 1 sulfur and 0, 1 or 2 nitrogen atoms said 5-membered heteroaromatic ring being attached via carbon and being optionally substituted with one or more groups which may be the same or different selected from X″; or

a 6-membered heteroaromatic ring containing one or two heteroatoms selected from 0 or 1 oxygen, 0 or 1 sulfur and 0, 1 or 2 nitrogen atoms said 6-membered heteroaromatic ring being attached via carbon and being optionally substituted with one or more groups which may be the same or different selected from X″;

Q′ is H; C₁-C₆alkyl optionally substituted with one or more halogen, CN, C₁-C₃alkoxy, C₁-C₆alkoxycarbonyl, or phenyl optionally substituted with one or more halogen, CN, NO₂, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkylsulfonyl or C₁-C₄alkylsulfinyl groups;

C₂-C₆alkenyl; C₂-C₆alkynyl; or phenyl optionally substituted with one to three groups, which may be the same or different, selected from X″;

R₂₃, R₂₄, R₂₅, R₂₆, R₂₇, R₂₈ and R₂₉ are each independently H or C₁-C₄alkyl; and the dotted line configuration represents a double bond or a single bond (i.e. C—N or C═N); or

a stereoisomer thereof.

Further preferred neuronal sodium channel antagonist compounds of the invention are those compounds of formula IV or V wherein the dotted line configuration represents a double bond.

Other preferred neuronal sodium channel antagonist compounds suitable for use in the composition of the invention are those compounds of formula IV or V wherein W is O; X″ and Y″ are each independently H or C₁-C₆haloalkyl; m is 1; R₂₃, R₂₄, R₂₅, R₂₆ and R₂₇ are each H; G is phenyl optionally substituted with one or more halogen atoms; Q′ is halophenyl or C₁-C₄alkyl optionally substituted with one phenyl or halophenyl group; and the dotted line configuration represents a double bond; or a stereoisomer thereof.

Arylpyrrole insecticides include those described in U.S. Pat. Nos. 5,010,098; 5,492,925; 5,484,807 and 5,284,863, among other publications. Exemplary of the arylpyrrole insecticides suitable for use in the composition of the invention are those arylpyrroles having the structural formula

Hal is Cl or Br;

x is an integer of 1, 2, 3, 4, 5 or 6;

D is H; C₁-C₆alkyl optionally substituted with one or more halogen, CN, OH, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₅alkylthio, C₁-C₄alkylcarbonyloxy, C₁-C₄haloalkylthio, C₁-C₆alkenylcarbonyloxy, phenylcarbonyloxy, halophenylcarbonyloxy, phenoxy, halophenoxy, phenyl, halophenyl or C₁-C₃alkylphenyl groups,

C₂-C₆alkenyl; C₂-C₆haloalkenyl; CN; C₂-C₆alkynyl; C₂-C₆haloalkynyl; di-(C₁-C₄alkyl)aminocarbonyl; or C₃-C₆polymethyleneiminocarbonyl;

L is H or halogen;

M and M′ are each independently H, halogen, CN, NO₂, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₄alkylthio, C₁-C₄haloalkylthio, C₁-C₄alkylsufonyl, C₁-C₄haloalkylsulfonyl, C₁-C₄alkylcarbonyl, C₁-C₄haloalkylcarbonyl, NR₃₅R₃₆ or when M and M¹ are attached to adjacent carbon atoms, they may be taken together with the carbon atoms to which they are attached to form a ring in which MM¹ represents —OCH₂O—, —OCF₂O— or —CH═CH—CH═CH—;

A′ is O or S;

R₃₀, R₃₁ and R₃₂ are each independently hydrogen, halogen, NO₂, CHO or R₃₁ and R₃₂ may be taken together with the carbon atoms to which they are attached to form a ring in which R₃₁R₃₂ represent

L′, L″, T and V are each independently H, halogen, CN or NO₂ with the proviso that no more than two of L′, L″, T or V are NO₂; and

R₃₅ and R₃₆ are each independently H or C₁-C₄alkyl.

Preferred arylpyrroles suitable for use as one essential active ingredient in the composition of the invention are those arylpyrroles of formula VI wherein D is H or ethoxymethyl; Ar is phenyl substituted with one or more halogen or halomethyl groups; and n is 1.

Preferred embodiments of the invention are those having a neuronal sodium channel antagonist compound of formula I or formula III and an arylpyrrole compound of formula VI as active ingredients.

More preferred embodiments of the invention are those having a formula I or formula III compound wherein W is O; X is trifluoromethoxy and is in the 4-position; Y is trifluoromethyl and is in the 3-position; Z is CN and is in the 4-position; A is CH₃; n is 0; m, p and q are each independently 1; R and R₁ are each independently H; Z is Cl;, R₃₃ and G are each independently CO₂CH₃; Q is p-(trifluoromethoxy)phenyl; and the dotted line configuration represents a double bond and a formula VI arylpyrrole wherein D is H or ethoxymethyl; Ar is phenyl substituted with one or more halogen or halomethyl groups; and x is 1.

Particularly preferred embodiments of the invention are those having as the active ingredients a compound of formula I or III wherein W is O; X is trifluoromethoxy and is in the 4-position; Y is trifluoromethyl and is in the 3-position; Z is CN and is in the 4-position; A is CH₃; n is 0; m, p and q are each 1; R and R₁ are each H; Z′ is Cl;, R₃₃ and G are each CO₂CH₃; and Q is p-(trifluoromethoxy)phenyl, and the dotted line configuration represents a double bond and an arylpyrrole of formula VI wherein D is H or ethoxymethyl; Ar is p-chlorophenyl or 3,5-dichlorophenyl; and x is 1.

In the specification and claims the term haloalkyl designates an alkyl group C_(x)H_(2x+1) having 1 to 2x+1 halogen atoms which may be the same or different. Similarly, the terms haloalkenyl, haloalkynyl, haloalkoxy, halophenyl and the like designate mono- to perhalogen substitution wherein the halogens may be the same or different. Halogen designates Cl, Br, I or F.

Each of the compounds of formula I, II, III, IV and V embody assymetric centers which may be represented in the stereoisomeric R-form or S-form. The present invention also includes the R-form, the S-form or mixtures comprising the R-form and the S-form in any ratio. For compounds of formula III, the S-form is preferred.

Advantageously, the neuronal sodium-channel antagonist compound of formula I, II, III, IV or V or a mixture thereof may be formulated with an arylpyrrole insecticide. Said formulation may then be dispersed in a solid or liquid diluent for application to the insect, its food supply, breeding ground or habitat as a dilute spray or as a solid dust or dust concentrate. Customary formulation adjuvants as well as additional agriculturally acceptable active ingredients may be added and are within the scope of the invention.

The active ingredients of the inventive composition may also be formulated separately as a wettable powder, emulsifiable concentrate, aqueous or liquid flowable, suspension concentrate or any one of the conventional formulations used for insect control agents and tank mixed in the field with water or other inexpensive liquid for application as a liquid spray mixture. The separately formulated compositions may also be applied sequentially.

In actual practice, the composition of the invention is applied to the plant foliage or plant stem or insect habitat as a dilute spray prepared from any of the above-said formulations. In practice it has been found that the active ingredients of the composition of the invention are highly synergistic when present at a ratio of neuronal sodium channel antagonist compound to arylpyrrole insecticide of about 1:10 to 1:50.

The compositions of the invention are superior insecticidal compositions and are especially useful for protecting growing and harvested plants including: leguminous crops such as soybeans, snap beans, peas, wax beans and the like as well as cotton, forage crops, cole crops, leafy vegetables, tobacco, hops, tomatoes, potatoes, flowering ornamentals such as chrysanthemums, vine crops such as grapes, squash, pumpkin or melon and fruit trees such as cherry, peach, apple or citrus, from the ravages of insects.

The synergistic insecticidal composition of the invention is found to be highly active against a wide variety of lepidopteran and coleopteran insects such as Helicoverpa zea (cotton bollworm), Heliothis virescens (tobacco budworm), Leptinotarsa decemlineata (Colorado potato beetle), Diabrotica spp. (corn rootworm) and the like.

Further, the composition of the invention may be useful in the prevention and control of public health pests such as houseflies, mosquitoes, cockroaches, ants, termites or the like.

These and other advantages of the invention may become more apparent from the examples set forth herein below. These examples are provided merely as illustrations of the invention and are not intended to be construed as a limitation thereof.

EXAMPLE 1

Evaluation of the Synergistic Insecticidal Effect of a Combination of a Neuronal Sodium Channel Antagonist Plus an Arylpyrrole Insecticide

In this evaluation, the Heliothis zea (cotton bollworm), Heliothis virescens (tobacco budworm) and pyrethroid-resistant Heliothis virescens larvae used are obtained from laboratory colonies. Pyrethroid-resistant H. virescens are derived from the PEG-strain [Campannola & Plapp, Proceedings of Beltwide Cotton Conference (1988)].

Cotton leaves are immersed in 1:1 v/v, acetone/water solutions of test compound, or solutions of a combination of test compounds for a period of about 3 seconds. Following immersion, leaves are allowed to air-dry for 2-3 hours. Plastic bioassay trays containing multiple open-faced wells (4.0×4.0×2.5 cm) are used as the test arenas. Cut portions of a treated leaf, a moistened cotton dental wick and a single third-instar larva are placed into each well, covered with an adhesive vented clear plastic sheet and held under constant fluorescent light at about 27° C. for a predetermined period of time. Larval mortality/morbidity is evaluated at 5 days after treatment. All treatments are replicated 4-5 fold in a randomized complete block design with 16-32 larvae per treatment. A log-probit analysis is applied to all data obtained. The results are summarized in Tables I, II and III hereinbelow.

TABLE I Evaluation of the Synergistic Control of Cotton Bollworm % Larval Toxicity Treatment Dose (ppm) Mortaliity Ratio^(3,4) A¹ 0.816 0 — B² 0.0816 9 — A + B 0.816 + 0.0816 50 5.6 A 1.0 9.4 — B 0.1 19.8 — A + B 1.0 + 0.1  62.5 2.1 ¹A = formula VIa arylpyrrole ²B = formula Ia neuronal sodium channel antagonist ${\quad^{3}{Toxicity}\quad {Ratio}} = \frac{\% \quad {mortality}\quad \left( {A + B} \right)}{{\% \quad {mortality}\quad A} + {\% \quad {mortality}\quad B}}$

⁴Toxicity Ratio > 1 = synergistic

TABLE II Evaluation of the Synergistic Control of Tobacco Budworm % Larval Toxicity Treatment Dose (ppm) Mortaliity Ratio^(3,4) A¹ 0.974 3 — B² 0.0974 25 — A + B 0.974 + 0.0974 50 1.8 A 1.0 10 — B 0.1 30 — A + B 1.0 + 0.1 51.3  1.28 ¹A = formula VIa arylpyrrole ²B = formula Ia neuronal sodium channel antagonist ${\quad^{3}{Toxicity}\quad {Ratio}} = \frac{\% \quad {mortality}\quad \left( {A + B} \right)}{{\% \quad {mortality}\quad A} + {\% \quad {mortality}\quad B}}$

⁴Toxicity Ratio > 1 = synergistic

TABLE III Evaluation of the Synergistic Control of Pyrethroid- Resistant Tobacco Budworm % Larval Toxicity Treatment Dose (ppm) Mortaliity Ratio^(3,4) A¹ 0.997 0 — B² 0.0997 29 — A + B 0.997 + 0.0997 50 1.7 A 2.093 7 — B 0.0419 8 — A + B 2.093 + 0.0419 50 3.3 A 1.0 6.2 — B 0.1 25.0 — A + B 1.0 + 0.1 56.3 1.8 A 3.0 34.4 — B 0.06 14.1 — A + B 3.0 + 0.06 81.2  1.67 ¹A = formula VIa arylpyrrole ²B = formula Ia neuronal sodium channel antagonist ${\quad^{3}{Toxicity}\quad {Ratio}} = \frac{\% \quad {mortality}\quad \left( {A + B} \right)}{{\% \quad {mortality}\quad A} + {\% \quad {mortality}\quad B}}$

⁴Toxicity Ratio > 1 = synergistic 

What is claimed is:
 1. A synergistic insecticidal composition comprising as active components (a) a neuronal sodium channel antagonist of formula III

 wherein W is O or S; Z′ is, in each case, independently selected from the group consisting of H; halogen; OH; CN; NO₂; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₃alkoxy, C₁-C₃haloalkoxy, C₃-C₆cycloalkyl, C₂-C₆alkenyloxy or sulfonyloxy groups; C₁-C₆alkoxy optionally substituted with one or more halogen, C₁-C₃alkoxy or C₃-C₆cycloalkyl groups; C₁-C₆alkoxycarbonyl, C₃-C₆cycloalkylcarbonyloxy, phenyl optionally substituted with one or more halogen, C₁-C₄alkyl, or C₁-C₄alkoxy groups; and aminocarbonyloxy optionally substituted with one or more C₁-C₃alkyl groups; t is an integer of 1, 2, 3 or 4; G is H; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₄alkoxy, C₁-C₆haloalkoxy, CN, NO₂, S(O)_(u)R₁₄, COR₁₅, CO₂R₁₆, phenyl or C₃-C₆cycloalkyl groups; C₁-C₆alkoxy; C₁-C₆haloalkoxy; CN; NO₂; S(O)_(u)R₁₇; COR₁₈; CO₂R₁₉; phenyl optionally substituted with one or more halogen, CN, C₁-C₃haloalkyl, or C₁-C₃haloalkoxy groups; C₃-C₆cycloalkyl; or phenylthio; Q is phenyl optionally substituted with one or more halogen, CN, SCN, NO₂, S(O)_(u)R₂₀, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxyalkyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, or NR₂₁R₂₂ groups; u is an integer of 0, 1 or 2; R₁₄, R₁₅, R₁₆, R₁₈, R₁₉, R₂₁ and R₂₂ are each independently H or C₁-C₆alkyl; R₁₇ and R₂₀ are each independently C₁-C₆alkyl or C₁-C₆haloalkyl; R₃₃ is CO₂R₃₄; R₃₄ is H, C₁-C₆alkyl, C₁-C₆haloalkyl, phenyl or halophenyl; and the dotted line configuration represents a double bond or a single bond; and (b) an arylpyrrole insecticide of formula VI

Hal is Cl or Br; x is an integer of 1, 2, 3, 4, 5 or 6; D is H, C₁-C₆alkyl optionally substituted with one or more halogen, CN, OH, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₅alkylthio, C₁-C₄alkylcarbonyloxy, C₁-C₄haloalkylthio, C₂-C₆alkenylcarbonyloxy, phenylcarbonyloxy, halophenylcarbonyloxy, phenoxy, halophenoxy, phenyl, halophenyl or C₁-C₃alkylphenyl groups, C₂-C₆alkenyl, C₂-C₆haloalkenyl, CN, C₂-C₆alkynyl, C₂-C₆haloalkynyl, di-(C₁-C₄alkyl) aminocarbonyl or C₃-C₆polymethyleneiminocarbonyl; L is H or halogen; M and M¹ are each independently H, halogen, CN, NO₂, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₄alkylthio, C₁-C₄haloalkylthio, C₁-C₄alkylsufonyl, C₁-C₄haloalkylsulfonyl, C₁-C₄alkylcarbonyl, C₁-C₄haloalkylcarbonyl, NR₃₅R₃₆ or when M and M¹ are attached to adjacent carbon atoms, they may be taken together with the carbon atoms to which they are attached to form a ring in which MM¹ represents —OCH₂O—, —OCF₂O— or —CH═CH—CH═CH—; A′ is O or S; R₃₀, R₃₁ and R₃₂ are each independently hydrogen, halogen, NO₂, CHO or R₃₁ and R₃₂ together with the carbon atoms to which they are attached to form a ring in which R₃₁R₃₂ represent

L′, L″, T and V are each independently H, halogen, CN or NO₂ with the proviso that no more than two of L′, L″, T or V are NO₂; and R₃₅ and R₃₆ are each independently H or C₁-C₄alkyl, and wherein components (a) and (b) are present in synergistically effective amounts.
 2. The composition according to claim 1 wherein Ar is the radical


3. A method for synergistic insect control which comprises contacting said insect with a combination of (a) a neuronal sodium channel antagonist of formula III

 wherein W is O or S; Z′ is, in each case, independently selected from the group consisting of H; halogen; OH; CN; NO₂; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₃alkoxy, C₁-C₃haloalkoxy, C₃-C₆cycloalkyl, C₂-C₆alkenyloxy or sulfonyloxy groups; C₁-C₆alkoxy optionally substituted with one or more halogen, C₁-C₃alkoxy or C₃-C₆cycloalkyl groups; C₁-C₆alkoxycarbonyl, C₃-C₆cycloalkylcarbonyloxy, phenyl optionally substituted with one or more halogen, C₁-C₄alkyl, or C₁-C₄alkoxy groups; and aminocarbonyloxy optionally substituted with one or more C₁-C₃alkyl groups; t is an integer of 1, 2, 3 or 4; G is H; C₁-C₆alkyl optionally substituted with one or more halogen, C₁-C₄alkoxy, C₁-C₆haloalkoxy, CN, NO₂, S(O)_(u)R₁₄, COR₁₅, CO₂R₁₆, phenyl or C₃-C₆cycloalkyl groups; C₁-C₆alkoxy; C₁-C₆haloalkoxy; CN; NO₂; S(O)_(u)R₁₇; COR₁₈; CO₂R₁₉; phenyl optionally substituted with one or more halogen, CN, C₁-C₃haloalkyl, or C₁-C₃haloalkoxy groups; C₃-C₆cycloalkyl; or phenylthio; Q is phenyl optionally substituted with one or more halogen, CN, SCN, NO₂, S(O)_(u)R₂₀, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxyalkyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, or NR₂₁R₂₂ groups; u is an integer of 0, 1 or 2; R₁₄, R₁₅, R₁₆, R₁₈, R₁₉, R₂₁ and R₂₂ are each independently H or C₁-C₆alkyl; R₁₇ and R₂₀ are each independently C₁-C₆alkyl or C₁-C₆haloalkyl; R₃₃ is CO₂R₃₄; R₃₄ is H, C₁-C₆alkyl, C₁-C₆haloalkyl, phenyl or halophenyl; and the dotted line configuration represents a double bond or a single bond; and (b) an arylpyrrole insecticide of formula VI

Hal is Cl or Br; x is an integer of 1, 2, 3, 4, 5 or 6; D is H, C₁-C₆alkyl optionally substituted with one or more halogen, CN, OH, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₅alkylthio, C₁-C₄alkylcarbonyloxy, C₁-C₄haloalkylthio, C₂-C₆alkenylcarbonyloxy, phenylcarbonyloxy, halophenylcarbonyloxy, phenoxy, halophenoxy, phenyl, halophenyl or C₁-C₃alkylphenyl groups, C₂-C₆alkenyl, C₂-C₆haloalkenyl, CN, C₂-C₆alkynyl, C₂-C₆haloalkynyl, di-(C₁-C₄alkyl) aminocarbonyl or C₃-C₆polymethyleneiminocarbonyl; L is H or halogen; M and M¹ are each independently H, halogen, CN, NO₂, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₄alkylthio, C₁-C₄haloalkylthio, C₁-C₄alkylsufonyl, C₁-C₄haloalkylsulfonyl, C₁-C₄alkylcarbonyl, C₁-C₄haloalkylcarbonyl, NR₃₅R₃₆ or when M and M¹ are attached to adjacent carbon atoms, they may be taken together with the carbon atoms to which they are attached to form a ring in which MM¹ represents —OCH₂O—, —OCF₂O— or —CH═CH—CH═CH—; A′ is O or S; R₃₀, R₃₁ and R₃₂ are each independently hydrogen, halogen, NO₂, CHO or R₃₁ and R₃₂ together with the carbon atoms to which they are attached to form a ring in which R₃₁R₃₂ represent

L′, L″, T and V are each independently H, halogen, CN or NO₂ with the proviso that no more than two of L′, L″, T or V are NO₂; and R₃₅ and R₃₆ are each independently H or C₁-C₄alkyl, and wherein components (a) and (b) are applied in synergistically effective amounts.
 4. The method according to claim 3 wherein Ar is the radical


5. The composition according to claim 1 wherein the ratio of the neuronal sodium channel antagonist to the arylpyrrole insecticide is about 1:10 to 1:50.
 6. The composition according to claim 5 wherein said neuronal sodium channel antagonist and said arylpyrrole insecticide are dispersed in an inert solid or liquid diluent.
 7. The composition according to claim 1 wherein the dotted line configuration represents a double bond.
 8. The composition according to claim 7 wherein the formula III compound is in the S-form.
 9. The composition according to claim 8 wherein W is O; X is trifluoromethoxy and is in the 4-position; Y is trifluoromethyl and is in the 3-position; Z is CN and is in the 4-position; A is CH₂; n is 0; m, p and q are each independently 1; R and R₁ are each independently H; Z′ is Cl; R₃₃ and G are each independently CO₂CH₃; and Q is p-(trifluoromethoxy)phenyl.
 10. The composition according to claim 1 wherein D is H or ethoxymethyl; Ar is phenyl substituted with one or two halogen or halomethyl groups; and x is
 1. 11. The method according to claim 3 wherein the neuronal sodium channel antagonist is present in a ratio to the arylpyrrole insecticide of about 1:10 to 1:50.
 12. The method according to claim 3 wherein the dotted line configuration represents a double bond.
 13. The method according to claim 12 wherein the formula III compound is in the S-form.
 14. The method according to claim 13 wherein W is O; X is trifluoromethoxy and is in the 4-position; Y is trifluoromethyl and is in the 3-position; Z is CN and is in the 4-position; A is CH₂; n is 0; m, p and q are each independently 1; R and R₁ are each independently H; Z′ is Cl; R₃₃ and G are each independently CO₂CH₃; and Q is p-(trifluoromethoxy)phenyl.
 15. The method according to claim 3 wherein D is H or ethoxymethyl; Ar is phenyl substituted with one or two halogen or halomethyl groups; and x is
 1. 16. A method for protecting a plant from infestation and attack by insects which comprises applying to the foliage or stem of said plant a synergistically effective amount of a composition according to claim
 1. 17. The method according to claim 16 wherein the plant is cotton.
 18. The method according to claim 16 wherein the insect is lepidoptera or coleoptera. 